Re: wind power generation
I may well be wrong, but I believe that the size of the rotor and the rotating speed do not influence the output.
The point is the electromagnetic converter, the motor you use as a dynamo/alternator: the rotating magnets produce an electromotor force (i.e. electric potential) which depends on the number of coils of electric wire that surrounds them. The current they can produce this way will depend on the rotation speed, and therefore on the size of the fan and the strength of the wing. But not the potential.
It is like imagining a 1 kg weight sitting on a 1 cm² transverse-area piston: it will generate a pressure of 1 kg/cm²; then if you raise it 20 times per second you certainly can pump more water out of the syringe than if you only raise it 2 times per second, but the pressure it can generate will never exceed 1 Kg/cm².
Still, I may be wrong...